Multistable Trusses of Nonlinear Morphing Elements

Current compliant mechanisms rely on flexible members, whose design is often limited by strength considerations. A compliant multistable truss is introduced that consists of nonlinear morphing elements. These elements: (i) are composed of composite strips in a double-helix architecture; (ii) exhibit nonlinear stiffness characteristics; and (iii) are able to undergo large axial deformations whilst maintaining structural integrity. The overall truss behaviour can be tailored by tuning the properties of the constituent composite members, as well as the geometry of the assembled structure. This work explores the multistability of a simple truss configuration, which can provide up to five points of stable equilibrium in its range of motion.